FERN TRIBE 129 
2. Toothed Bladder-fern (C. dentdta).— Fronds oblong-ianceolate, 
twice pinnate ; pinnules egg-shaped, obtuse, bluntly toothed. This plant is 
so similar to the Brittle Bladder-fern that some writers describe it merely as 
a variety of that plant, but Mr. Babington and several other writers on ferns 
considered it a distinct species. It is a smaller plant, its pinns being more 
horizontal in form, and all its parts more blunt. Its veining is similar, but 
the fructification is at the termination and not near the middle of the 
secondary vein, and is thus more distinctly marginal. The clusters are at 
first separate, but as they ripen they run into a mass, and form a brown 
ridge on the under surface of the pinnules. This constitutes a very marked 
difference between this and the Brittle Bladder-fern. The smooth slender 
rachis is almost always of a brownish-purple colour. 
The Toothed Bladder-fern is not uncommon in the north of England, as 
about Settle, in Yorkshire, at Cauldron Snout, Durham, and various other 
localities. It is found, too, near Matlock Baths, on the Cheddar Cliffs, at 
Tunbridge Wells, and numerous other spots throughout the kingdom where 
the soil is rocky, though it is probably often overlooked and mistaken for 
Cystépteris fragilis. 
A most marked variety of this fern, termed Dickicana, has a very compact 
frond, and is a very beautiful plant, of a deep green colour, and almost 
transparent texture. The general outline is nearly egg-shaped, but ter- 
minating in a point, and the pinne are egg-shaped and lanceolate, over- 
lapping each other, the pinnules running closely together so as to form a 
wing. They are broad and blunt, with a few shallow marginal notches, and 
the fructification is also marginal. Dr. Dickie discovered this remarkable 
variety in 1846. He found it growing in a sea-cave near Aberdeen. No 
other native locality of this plant is recorded, but it is well known to the 
cultivator of ferns, retaining its peculiarities in the greenhouse or closed 
case. Its height varies from about four to six inches. 
3. Alpine Bladder-fern, or Laciniated Bladder-fern (C. alpina).— 
Fronds lanceolate, thrice pinnate ; pinnules deeply pinnatifid, partly cloven, 
and slightly toothed at the end. This plant is the loveliest of this 
exquisitely beautiful genus. It formerly grew in abundance on an old wall 
at Low Leyton in Essex, but the only known locality for it now is in Teesdale, 
Yorks. Sir Wm. Hooker and Dr. Arnott, who examined specimens of the 
Leyton Fern, pronounced it to be identical with the Continental species. Its 
fronds, which are very numerous, grow in tufts. They are usually about 
four or five inches high, but are sometimes twice that height, appearing 
in May, but, like their equally delicate congeners, dying away with the 
earliest frosts of autumn. The lanceolate frond is twice pinnate, and the 
pinnules are often so deeply pinnatifid as to be almost distinct. The 
branches, which are nearly opposite, with a winged rachis, are egg-shaped, 
and divided into bluntly egg-shaped pinnules, these pinnules being again cut 
down almost to the mid-vein into short blunt lobes, which are partly cloven, 
and slightly toothed at the end. The mid-vein of the pinnules is. distinct 
and nearly straight, with a side vein, either simple or divided, issuing into 
each lobe, one branch extending to the point of each marginal serrature. 
Numerous rounded clusters of capsules lie near the margin, covered with 
Iv.—17 
